Microgreens on a Windowsill: Tiny Plants, Tiny Budget

I bought a bag of microgreens at the grocery store last winter. Four ounces. The price made me set it back down and stare at it for a second like it had personally offended me. Then I walked home and started researching how to grow them myself, which is honestly just how I respond to most problems.

Turns out microgreens are one of the easiest, cheapest things you can grow indoors, and they don’t care that it’s grey and drizzly outside for six months. No grow lights required if you have a decent south-facing window. Which, in the Pacific Northwest in May, means you are finally, actually in business.

What You Actually Need

A shallow tray, some growing medium, seeds, water, and a windowsill. That’s the whole list. I’ve grown them in takeout containers with holes poked in the bottom. Old baking pans. The plants do not care about the aesthetic. Neither do I, frankly.

For growing medium, I use a thin layer of coconut coir, maybe an inch deep. It’s cheap, holds moisture well, and doesn’t get as funky as potting soil in a shallow tray. You can also use plain potting mix if that’s what you have. Both work fine.

The Seeds Are Where It Gets Fun

Almost anything germinates fast and tastes good as a microgreen. Radish is the beginner’s best friend. Ready to harvest in about 7 days, spicy and satisfying, practically unkillable. Sunflower, peas, broccoli, mustard, amaranth, cilantro (which I always want to call coriander because I’ve been growing it too long). All great options.

The budget-brain move: buy seeds in bulk. A small packet from the garden center is fine for a first try, but once you’re hooked you’ll want a bulk bag of radish or sunflower seeds. Way cheaper per tray. I’ve also had good luck with microgreens seed mixes from seed catalogs, usually a decent variety without paying specialty-shop prices.

One thing I did wrong early on: I bought herb seeds marketed specifically as microgreens and paid way too much for them. Regular radish seeds from the bulk bin at Sky Nursery grow the exact same radish microgreen. Lettuce is lettuce. Lesson learned, eventually, after spending more than I needed to on seeds that came in fancier packaging.

The Method (Genuinely Simple)

Moisten your coir before it goes in the tray. Dry coir repels water at first, and if you water from the top after seeding you’ll wash everything around. Learned that one the hard way. Spread it about an inch deep, press it flat.

Scatter seeds fairly densely. Not buried, just laid on top and pressed in gently with your hand. For small seeds like radish or broccoli, you want them close together but not piled up. Think of it like tiling a very tiny floor. A floor you’re going to eat in ten days.

Cover the tray with another tray or a piece of cardboard for the first two to three days. Keeps moisture in and gives the seeds the darkness they want for germination. Once they’ve sprouted and started reaching for light, pull the cover off and set them in the window.

Water from the bottom when you can. Just pour a little into the tray underneath and let the coir wick it up. Top watering works too, just be gentle. A spray bottle is great here and costs almost nothing at McLendon Hardware.

Harvesting

Harvest when the first true leaves appear, usually right after the seed leaves fully open. For most varieties that’s somewhere between 7 and 14 days. Grab a handful and cut at the base with scissors. Rinse them off and eat them that day. They don’t keep great once cut, which is actually an argument for growing small batches more often rather than one giant tray all at once.

I started doing two small trays a week apart. Continuous supply, no waste. Which, now that I think about it, is basically succession planting but faster and on my kitchen windowsill. My oldest saw me doing it and said it looked like a tiny farm. She wasn’t wrong.

May Timing in the PNW

May is actually the sweet spot for windowsill microgreens here. We’re finally getting enough light hours that a south-facing window does real work, but it’s not hot enough to stress the seedlings. If your window runs warm later in summer, you might get some leggy growth or mold issues. For now though, conditions are good.

And if you don’t have a great south window, a cheap LED grow light strip on a timer handles it fine. Microgreens don’t need much. Around 1000 to 1500 lumens is plenty for these little guys. They’re not asking for a lot. Just water, a little light, and the chance to become a salad.

Lettuce be honest: this is the fastest return on investment in the entire garden. Ten days from seed to table, practically no cost, and they taste better than anything in that overpriced bag at the store. That one’s for free.

Photo by Sudhan Chitgopkar on Unsplash